JP7349778B2 - Abradable seal composition for turbomachinery compressors - Google Patents

Description

The present invention relates to the field of turbomachinery sealing using two-phase abradable seals. The invention also proposes a method of manufacturing an abradable seal. The present invention relates to compressors and axial flow turbomachines, and in particular to aircraft jet engines or aircraft turboprop engine machines.

Mechanical gaps between the rotor blade tip and the surrounding casing cause leakage, reducing the performance of the turbomachinery compressor. To reduce leakage, it is essential to reduce the distance between the rotor blade and the casing while ensuring a safety margin. In fact, the safe operation of the turbomachinery can be jeopardized, as both the rotor blade and the casing are damaged in the event of contact. Such events occur frequently due to vibrations, suction, centrifugal forces, expansion, rotor eccentricity, among others. Therefore, by adding a layer of abradable material at the interface between the casing and the rotor blade, damage on contact is controlled, since the damage is limited only to the frangible material of the seal. becomes possible.

US Pat. No. 5,090,301 discloses an abradable seal composition for turbomachinery, the composition comprising an aluminum base, nickel powder, and polyester powder. This document teaches an outer casing for an axial flow turbomachinery low pressure compressor having an abradable seal surrounding an annular row of rotor blades. The seal comprises a circular substrate covered with a layer of abradable material containing a metallic phase consisting mainly of aluminum and a small amount of nickel. The abrasive material further includes 25% to 55% additives such as polyester, methyl methacrylate, hexagonal boron nitride, and calcium fluoride. The base is sectioned to form an organic matrix outer casing composition of the compressor. In this way, the properties of this seal are improved. Additionally, the seal remains a composite for application.

European Patent Application No. 3023511 European Patent Application No. 1010861

The present invention aims to solve at least one of the problems presented by the prior art. More specifically, the invention has the aim of optimizing the brittle nature of the seal. The invention also proposes a solution that is simple, durable, lightweight, economical, reliable, easy to manufacture, maintain and test, and improves efficiency.

The present invention relates to a composition of an abradable seal for a turbomachine, in particular in powder form, said seal being able to shatter when in contact with the rotor of said turbomachine, said composition being based on aluminium. It comprises a metallic phase and a second phase comprising inorganic and/or organic material, in particular the metallic phase further comprising chromium. The metallic phase further includes nickel. The metallic phase contains more chromium than nickel.

The addition of nickel, which has interesting physical properties, especially in hardness/toughness, allows for a better balance between hardness/toughness and cost in abradable seals. Based on advantageous embodiments of the invention, the composition can have one or more of the following features, which can be alone or in any technical combination:
The metallic phase contains 20-45% by weight of chromium.
The organic material includes polyester and the inorganic material includes hexagonal boron nitride.
The metallic phase is composed of aluminum and chromium.
The metallic phase accounts for 50-90% of the weight of the composition.
The metallic phase accounts for 82-90% of the mass of the composition.
The second phase accounts for 10-50% of the weight of the composition.
The second phase accounts for 10-25% of the weight of the composition.
The second phase includes at least one of polyimide, polyamideimide, polyetherimide, bismaleimide, fluororesin, ketone resin, liquid crystal polymer, or a combination thereof.
The second phase includes at least one material that is molybdenum disulfide, graphite, talc, bentonite, mica, or a combination thereof.

The present invention relates to a composition of an abradable seal for a turbomachine, in particular in powder form, said seal being able to shatter when in contact with the rotor of said turbomachine, said composition comprising an aluminium-based metal phase and a second phase comprising inorganic and/or organic materials, in particular said metallic phase accounts for 80-90% of the weight of said composition, and/or at least 81% of the weight of said composition. , 82% or 83%.

The present invention relates to a composition of an abradable seal for a turbomachine, in particular in powder form, said seal being able to shatter when in contact with the rotor of said turbomachine, said composition comprising an aluminium-based metal phase and a second phase comprising an inorganic material and/or an organic material, in particular the inorganic material accounts for 10-45% or 10-25% of the weight of the composition.

The present invention relates to a composition of an abradable seal for a turbomachine, in particular in powder form, said seal being able to shatter when in contact with the rotor of said turbomachine, said composition comprising an aluminium-based metal phase and a second phase comprising an inorganic material and/or an organic material, in particular the organic material accounts for 10-45% or 10-25% of the weight of the composition.

The present invention relates to a composition of an abradable seal for a turbomachine, in particular in powder form, said seal being able to shatter when in contact with the rotor of said turbomachine, said composition comprising an aluminium-based metal phase and a second phase, and particularly the second phase includes polyimide, polyamideimide, polyetherimide, bismaleimide, fluororesin, ketone resin, liquid crystal polymer, molybdenum disulfide, graphite, talc, bentonite, Contains at least one material that is mica or a combination thereof.

The present invention also relates to a compressor for turbomachinery, and in particular to a low-pressure compressor for turbomachinery, comprising a rotor with rotor blades and an abradable seal sealingly cooperating with said rotor blade, and in particular to a low-pressure compressor for turbomachinery, comprising a rotor with rotor blades and an abradable seal sealingly cooperating with said rotor blade. includes compositions according to the invention.

According to advantageous embodiments of the invention, the compressor can be equipped with one or more of the following features, which can be used alone or in any technical combination:
The compressor comprises: an organic matrix composition wall on which an abradable seal is disposed; and an interface between the organic matrix composition wall and the abradable seal, formed by a metal strip. Be prepared.
The rotor blades, which co-operate sealingly with the abradable seal, are made of titanium.
The rotor blades are configured to operate at transonic speeds.
The radial thickness of the abradable seal is greater than or equal to the average thickness of the rotor blade and/or greater than or equal to 3.00 mm.
The strips are made of iron, in particular of steel.
The degree of compression of seals made of abradable materials is greater than or equal to 90%, 95%, 98% or 99%.

The present invention relates to a turbomachine, in particular a jet engine, equipped with an abradable seal, the abradable seal being characterized in that the composition of the abradable seal is based on the invention; A compressor according to the invention can also be provided.

The present invention also relates to a method of manufacturing an abradable seal for a turbomachine, in particular a jet engine, said seal comprising an arcuate wall and an abradable composition applied to said arcuate wall. The method includes the following steps. (a) providing or manufacturing an arcuate wall; (f) applying an abradable sealing composition to the arcuate wall by thermal spraying, the composition comprising an aluminum-based metallic phase and a second phase, and in the applying step (f), at the beginning and/or at the end of the applying step (f), optionally said metal phase further comprises nickel and said composition is according to the invention. be.

In one advantageous form of the invention, during the applying step (f) said composition is applied by plasma spraying.

In general, advantageous embodiments of each object of the invention are also applicable to other objects of the invention. Each object of the invention can be combined with other objects, the object of the invention can also be combined with the embodiments of the specification, and furthermore, unless there are expressly stated to the contrary, technically possible combinations. can be mutual.

The presence of chromium in the abradable composition provides enhanced anchoring to the substrate. For example, the adhesion to metal strips is strengthened, especially to organic matrix composition casings.

At the same time, the brittle behavior of abrasive materials is enhanced by plasma spraying. This is due in particular to thorough mixing of the metallic phase and the second layer. Each of these forms smaller crystals compared to the prior art. The shape and surface of the crystals can lead to better interpenetration.

FIG. 1 shows an axial turbomachine according to the invention. FIG. 2 is a diagram of a turbomachine compressor according to the invention. FIG. 3 shows an abradable seal for turbomachinery according to the invention. FIG. 4 shows a diagram of a method of manufacturing an abradable seal for turbomachinery according to the invention.

In the following description, the terms "internal" and "external" refer to the position relative to the axis of rotation of the axial turbomachine. The axial direction corresponds to the direction along the rotation axis of the turbomachine. The radial direction is perpendicular to the axis of rotation. Upstream and downstream indicate the main flow directions in the turbomachine flow.

Metallic phase is understood as a physical property of a material.

Abradable materials are understood to be materials that crumble when in contact with the rotor elements of a turbomachine. This material is suitable for concentrating wear and deformation within the rotor while maintaining rotor integrity.

FIG. 1 is a simplified diagram of an axial flow turbomachine. This is a special example of a turbofan engine. Jet engine 2 comprises a first compression stage called low pressure compressor 4 , a second compression stage called high pressure compressor 6 , a combustion chamber 8 and one or more turbine stages 10 . In operation, the mechanical power of the turbine 10, transmitted through the central shaft of the rotor 12, drives the two compressors 4,6. The compressor 6 includes multiple rows of rotor blades associated with rows of stator blades. The rotation of the rotor around the rotation axis 14 creates an air flow that can be strongly compressed from the inlet to the combustion chamber 8.

An inlet fan 16 is coupled to the rotor blades 12 to create a flow of air that is split in the core flow 18 and passed through the various stages described above of the turbomachine and a bypass flow 20 to the annular pipe running along the machine. (as shown) and rejoins the core flow at the turbine exit. The acceleration of the bypass flow generates the thrust needed to fly the airplane. Core flow 18 and bypass flow 20 are coaxial, annular flows, one within the other. Core flow 18 and bypass flow 20 are routed by the turbomachine casing and/or bulkhead. To that end, the casing has an internally and externally facing cylindrical wall 21.

FIG. 2 is a cross-sectional view of the same axial turbomachinery compressor as FIG. 1. The compressor is a low pressure compressor 4. The figure shows a portion of fan 16 and a separator 22 that separates core flow 18 from bypass flow 20. The rotor 12 includes multiple rows of rotor blades 24, in this case three rows.

The low-pressure compressor 4 includes a plurality of stators, in this case four stators, each of which includes a row of stator vanes 26 . Certain vanes are adjustable in orientation, in which case they are referred to as variable pitch vanes. The front stator is associated with a fan 16 or a row of rotor blades for changing the air flow, thereby converting the velocity of said flow into pressure, in particular into static pressure.

Compressor 4 includes an outer casing 28 . This casing comprises an arcuate wall 30. This wall 30 may be shown as a monolithic closed hoop around the axis of rotation 14, or may be formed as a half shell or semicircle.

The casing 28 and in particular the casing wall 30 are made of an organic matrix composite material. The matrix is reinforced with fibers, which are in preformed form. The reinforcement may comprise a fiber layer, for example comprising carbon fibers or glass fibers.

The stator vanes 26 extend essentially radially from the wall 30 and are secured and mounted by pins 32 . Optionally, the stator vane includes a fixation platform 34 that receives a fixation pin 32. Both the stationary vane and the fixed base are made of titanium.

The stator vanes receive, by means of the casing 28, at least one annular seal 36, optionally around each annular row of rotor blades 24. The at least one or each annular seal 36 may be an abradable seal having an annular layer of abradable material 38. The seals are thus abradable seals 36 that can help reduce leakage by bringing the blades 24 and casing 28 into close proximity.

Optionally, internal bulkhead 40 is coupled to an internal end of vane 26 . The septa also receive abradable seals as described in the present invention and cooperate sealingly with the rotor 12.

FIG. 3 shows an abradable seal 36 for a compressor such as that shown in FIG. The figure shows the wall 34 of the casing 28 or substrate 28, the abradable layer 38 applied to the seal 36, and the end of the rotor blade 24 between the two vanes 26.

The abradable layer 38 extends from one platform 34 of the vane 26 to the next, belonging to an adjacent row located either upstream or downstream. The or each abradable seal may contact the platform material, optionally in electrical contact.

An abradable layer 38 is applied to the wall 30 of the casing 28. Furthermore, the seal 36 includes an intermediate layer between the substrate and the abradable layer 38. The intermediate layer may be a strip 42, such as a steel plate or a nickel plate. Said strip 42 can be perforated and/or cut. The strip 42 has a constant thickness. The abradable layer 38 can be thicker than the band 42.

The strip 42 may be secured to the wall 30 and/or carried by the platform 34 of the vane 26 . Optionally, the upstream and/or downstream ends of the strip 42 are secured between the platform 34 and the wall 30.

The abradable layer 38 has an interior surface 44 that contacts the core flow 18 . Its internal surface 44 guides and couples the core flow 18 during compression of the latter. It is flushed with the interior surface of platform 34.

The composition of material forming the abradable layer 38 and thereby the seal 36 may include at least two mixed phases, in particular a metallic phase and a second phase. Said second phase is inorganic and/or organic. The abradable material may be composite and/or granular and/or void filled with its constituent materials. The second phase can also form a lubricating oil.

The metallic phase mainly contains aluminum. The metallic phase of the composition is aluminum based. This means that the largest mass of metals in the abrasive material is aluminum. The advantage of aluminum is to optimize the mass of the seal 36. The metallic phase may include chromium in a lower mass proportion than aluminum.

The metallic phase contains 20% to 45% chromium and 55% to 80% aluminum. Aluminum and chromium may be the only two metals whose respective weights represent at least 0.10% or at least 1% of the weight of said composition. The metallic phase may be composed of aluminum and chromium.

Optionally, said metallic phase comprises nickel, in particular nickel which is smaller in mass proportion than chromium, for example by a factor of two.

For example, the metallic phase comprises 10% by weight of chromium and/or 5% by weight of nickel, or 30% by weight of chromium and 10% by weight of nickel.

Furthermore, said metallic phase optionally comprises iron, copper, zinc, manganese, magnesium and/or impurities, these compositions individually or in total amounting to 1% to 0.1% by weight of said metallic phase. shows.

The organic material of the second phase of the composition may be comprised of polymers such as polyesters, polyimides, polyamideimides, polyetherimides, bismaleimides, fluororesins, ketone resins, liquid crystal polymers, or any combination thereof. can be included.

The second phase can also include hexagonal boron nitride, calcium fluoride, molybdenum disulfide, graphite, talc, bentonite, mica, or any combination thereof. These materials are considered inorganic materials.

The second phase comprises a mixture of at least one inorganic material and at least one organic material.

The weight of the second phase corresponds to 5% to 50%, 15% to 25%, or 20% of the weight of the composition. The metallic phase may occupy the majority of the volume of the abradable layer, ie the metallic phase may form a matrix that receives the second phase.

Further, the abradable layer may be formed of particles of metal powder in which intergranular spaces are filled with the second phase. The voids within the abradable layer are less than 1%, preferably less than 0.1%.

FIG. 4 is an illustration of a method of manufacturing an abradable seal for an axial flow turbomachine such as that shown in FIGS. 2 and/or 3. Said seal is used in the compressors described in connection with FIG. 1 and/or FIG. 2, especially low pressure compressors.

The method includes the following steps performed in the following order.
(a) Step 100 of providing or manufacturing an arcuate wall that is the outer casing of a compressor, said wall acting as a substrate;
(b) Step 102 of providing or manufacturing the platform and stationary vanes.
(c) Providing or manufacturing a strip 104
(d) step 106 of installing the strip in the casing, in particular on the internal surface of the arcuate wall;
(e) fixing 108 the stationary vanes via their platforms to an arcuate wall forming an annular row;
(f) applying 110 an abradable composition to the arcuate walls between the annular rows of platforms so as to cover the strips;
At the beginning of the applying step (f) 110, the composition has a predominantly metallic phase comprising aluminum, for example in powder form. The aluminum may be pure aluminum or alloyed. The same is true for chrome.

The composition may include chromium on powder and optionally a second metal. The weight of chromium represents at least 20%, 21%, 22% or 23% by weight of the metallic phase. The composition of the powder may correspond to the chemical composition of the abradable layer presented above.

At the end of the applying step (f) 110, at least one compound or each compound of the composition remains in powder form, or at least one compound is molten, or each compound is molten.

Certain powder particles, at least one powder particle, or each powder particle may be essentially solid. Each particle can form a homogeneous material. Optionally, one type of particle is a hollow particle, such as an aluminum particle or a chromium particle.

During the applying step (f) 110, the composition is applied to the casing, ie the arcuate wall, by plasma spraying. This type of thermal technique is known to those skilled in the art and can be carried out in a manner similar to that disclosed in US Pat. The second phase powder can be introduced by plasma injection downstream of the metal powder. Other techniques can also be used. Alternatively, the composition can be applied to the substrate by baking, optionally by heating for an extended period of time. In this alternative, some of the particles may retain their original shape.

(b) providing 102 a stator vane; (c) providing or manufacturing a strip 104; (d) installing 106 said strip on an internal surface of said casing, in particular an arcuate wall; e) The step 108 of fixing said vanes is completely optional in the present invention. In fact, the abradable material composition can be applied to a substrate without moving or vanes and/or without a band. For example, (f) applying step 110 may be performed within a channel formed in the thickness of the arcuate wall and/or directly on the interior surface of the arcuate wall.

The characteristics defined in connection with the composition are also applicable to the seal, and vice versa.

Claims (12)

An abradable sealing composition for a turbomachine, the composition being capable of fraying upon contact with a rotor of the turbomachine;
The composition includes:
A metallic phase mainly composed of aluminum,
a second phase comprising an inorganic material and/or an organic material;
A composition for an abradable seal for a turbomachinery, wherein the metallic phase further includes chromium and nickel, the metallic phase containing more chromium than nickel, providing enhanced fixation to a substrate . The composition of claim 1, wherein the metallic phase comprises 20-45% by weight chromium. 2. The composition of claim 1, wherein the organic material comprises polyester and the inorganic material comprises hexagonal boron nitride. The composition of claim 1, wherein the metallic phase accounts for 82-90% of the weight of the composition. The composition of claim 1, wherein the second phase accounts for 10-25% of the weight of the composition. 2. The second phase includes at least one of polyimide, polyamideimide, polyetherimide, bismaleimide, fluororesin, ketone resin, liquid crystal polymer, or a combination thereof. Composition. 2. The composition of claim 1, wherein the second phase comprises at least one of the following materials: molybdenum disulfide, graphite, talc, bentonite, mica, or a combination thereof. A turbomachinery compressor comprising a rotor having rotor blades and a wall having an abradable seal sealingly cooperating with the rotor blade, the abradable seal comprising a composition;
The composition includes:
a metallic phase mainly composed of aluminum, the metallic phase further containing chromium and nickel, and containing more chromium than nickel, and
a second phase comprising an inorganic material and/or an organic material ;
A compressor for turbomachinery, providing enhanced fixation to said wall . The wall of the compressor comprises an organic matrix composition wall on which an abradable seal is disposed, and a joint between the organic matrix composition wall and the abradable seal formed of a metal strip. A compressor according to claim 8. 9. The compressor of claim 8, wherein the radial thickness of the abradable seal is greater than or equal to the average thickness of the rotor blade. A method for producing an abradable seal composition for a jet engine, the seal comprising an arcuate wall and an abrasive composition applied to the arcuate wall,
The method includes:
providing or manufacturing an arcuate wall;
Applying an abradable sealing composition to an arcuate wall by thermal spraying, the abradable sealing composition comprising a metallic phase mainly composed of aluminum and a second phase containing an inorganic material and/or an organic material. and the metallic phase further includes chromium and nickel, including more chromium than nickel ,
A method of providing enhanced fixation to said arcuate wall . 12. The method of claim 11, wherein during the applying step, the composition is applied by plasma spraying.